A Quad Flat No leads (QFN) package is a type of semiconductor device package having short signal traces and, thus, fast signal transmission speed. Therefore, QFN packages are well suited to chip packages with high frequency transmission (e.g. high frequency transmission through the RF bandwidth), and have become common for package applications in the wireless field, for example.
In one method of manufacturing a conventional QFN package, a lead frame having die pads and leads is provided. Each of the leads has a full thickness portion in the periphery of the package and a half etch portion extending from the full thickness portion toward the die pad. Chips, or dies, are configured on the die pads and electrically connected to the half etch portions of the leads via bonding wires. The half etch portion of the leads, the bonding wires, and the chips are encapsulated and protected by a molding compound, or encapsulant, and the bottom surfaces of the full thickness portions of the leads are exposed from the encapsulant for electrical connection to an external device. A punching process or a sawing process is then performed to divide the structure into individual QFN packages.
When the size of a QFN package is enlarged, the distance between the chip and the full thickness portions of the leads increases. Therefore the lengths of the half etch portions of the leads is also increase to save the lengths of the bonding wires. However, since the bottoms of the half etch portions of the leads are removed, the half etch portions of the leads may bounce during the wirebonding process due to lack of stiffness. Bouncing may cause one or more of the conductive wires to be bonded in the wrong position with respect to the leads, and the yield of the wirebonding process may decrease accordingly.